This study planned to evaluate 2 cohorts: up to 8 participants to receive 5 weekly intravenous (IV) doses of ALXN1830 at 10 milligram/kilogram (mg/kg) (Cohort 1) and up to 12 participants to receive 3 x 30 mg/kg weekly doses of ALXN1830 IV (loading) followed by 5 x 10 mg/kg doses of ALXN1830 IV every other week or 10 weekly doses of ALXN1830 IV (maintenance) (Cohort 2).
This study was terminated after the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and efficacy were characterized in participants with pemphigus at a single dose level (10 mg/kg) in Cohort 1, before any participants were enrolled in Cohort 2.
The study consisted of 3 periods: Screening, Treatment, and Follow-Up.
